1. Field of the Invention
The invention relates in general to a display device and a displaying method, and more particularly, to a region-based image display device and a region-based image displaying method.
2. Description of the Related Art
The backlight module of a conventional display device has a constant luminance. Therefore, when displaying images with different brightness, the luminance of the backlight module cannot be changed. Images with lower brightness are displayed using the same luminance used for displaying image with higher brightness. As a result, electrical power is wasted. Philips Electronics uses the Adaptive Dynamic Image Control cooperating with an in-plane switching mode display device. The whole luminance of the backlight module is dynamically adjusted according to the gray scale of the image. In other words, when the brightness of the image is high, the luminance value of the whole backlight module is adjusted to a higher value. When the brightness of the image is low, the luminance value of the whole backlight module is adjusted to a lower value. However, in general, the gray scale values of one image vary widely from one region of the image to another. Therefore, with the Adaptive Dynamic Image Control, different parts of one image with different gray scale values cannot be displayed by different luminance values at the same time. The luminance of the conventional backlight module cannot be adjusted effectively.